Imaging apparatus and method for recapturing an image captured in a multiple exposure shooting mode

ABSTRACT

An imaging apparatus receives an instruction to recapture an image last captured in a multiple exposure shooting mode after a first number of images in the multiple exposure shooting mode are acquired. The imaging apparatus generates an image into which an image captured in the multiple exposure shooting mode and a second number of images are multiple combined, the second number of images being the first number of images excluding the image last captured. The imaging apparatus displays, on a display unit, a first image obtained by multiple combining the first number of images and a second image obtained by multiple combining the second number of images after the first number of images are acquired in the multiple exposure shooting mode and before the instruction to recapture the image is received.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an imaging apparatus, and moreparticularly to an imaging apparatus that can multiple combine aplurality of captured images.

2. Description of the Related Art

There has conventionally been a technology of performing multipleexposure shooting through addition processing of a plurality of digitalimage signals.

Japanese Patent Application Laid-Open No. 2002-218313 discussesretaining three images in a recording area in the process of imagecapturing in a multiple exposure shooting mode. The three images to beretained include an image captured immediately before, an addition image(keep image) up to the previous image capturing, and an addition imageobtained by adding the addition image up to the previous image capturingand the image captured immediately before. Japanese Patent ApplicationLaid-Open No. 2002-218313 also discusses receiving an instruction toclear the image captured immediately before while the addition imageimmediately after the image capturing is displayed for a preview. Then,the image to be added to the keep image can be recaptured.

Japanese Patent Application Laid-Open No. 2006-340063 discussesproviding a preview display after each time an image is captured in amultiple exposure mode. During the preview display, an image previewswitch can be pressed each time to switch to display of a multipleexposure image in the captured image in a picture-in-picture fashion,display only the captured image, and display only the multiple exposureimage.

Consider the case of clearing an image captured immediately before forthe sake of recapturing as discussed in Japanese Patent ApplicationLaid-Open No. 2002-218313. In such a case, information for making adecision whether to clear the image captured immediately before(hereinafter, also referred to as immediately-previous image) may beobtained if a comparison can be made between the outcome when theimmediately-previous image is added to an existing addition image(multiple combined image) and the outcome when not added. However,according to Japanese Patent Application Laid-Open No. 2002-218313, itis only possible to display a multiple combined image obtained by addingall images captured in a multiple exposure shooting mode (an additionimage or a keep image during a through image display), not a multiplecombined image without the immediately-previous image added. Accordingto Japanese Patent Application Laid-Open No. 2006-340063 also, it isonly possible to display a multiple combined image obtained by addingall images captured in a multiple exposure shooting mode (multipleexposure image) and an immediately-previous image (captured image), butnot a multiple combined image without the immediately-previous image. Inother words, it has conventionally not been possible to compare theoutcome when an immediately-previous image captured immediately beforein the multiple exposure shooting mode is added to an existing multiplecombined image and the outcome when not added.

SUMMARY OF THE INVENTION

The present invention is directed to an imaging apparatus that enables acomparison between a multiple combined image to which an image capturedimmediately before is not added and a multiple combined image to whichthe image captured immediately before is added.

According to an aspect of the present invention, an imaging apparatusincludes a receiving unit configured to receive an instruction torecapture an image last captured in a multiple exposure shooting modeafter a first number of images are acquired in the multiple exposureshooting mode, a generation unit configured to generate an image intowhich an image that is captured in the multiple exposure shooting modeafter the instruction to recapture the image is received by thereceiving unit and a second number of images are multiple combined, thesecond number of images being the first number of images excluding theimage last captured, and a display control unit configured to display,on a display unit, a first image obtained by multiple combining thefirst number of images and a second image obtained by multiple combiningthe second number of images after the first number of images areacquired in the multiple exposure shooting mode and before theinstruction to recapture the image is received by the receiving unit.

According to an exemplary embodiment of the present invention, acomparison can be made between a multiple combined image to which animage captured immediately before is not added and a multiple combinedimage to which the image captured immediately before is added.

Further features and aspects of the present invention will becomeapparent from the following detailed description of exemplaryembodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate exemplary embodiments, features,and aspects of the invention and, together with the description, serveto explain the principles of the invention.

FIG. 1 is a configuration block diagram illustrating a digital cameraaccording to an exemplary embodiment of the present invention.

FIGS. 2A and 2B are external views of the digital camera.

FIGS. 3A and 3B are diagrams illustrating display examples of apresetting menu screen for multiple exposure shooting.

FIGS. 4A, 4B, 4C, 4D, and 4E are diagrams illustrating image data storedin a buffer memory during multiple exposure shooting.

FIG. 5 is a flowchart illustrating multiple exposure shooting modeprocessing.

FIG. 6 is a flowchart illustrating multiple exposure shootingprocessing.

FIGS. 7A and 7B are diagrams illustrating display examples of a quickreview in multiple exposure shooting.

FIG. 8 is a flowchart illustrating multiple quick review and playbackprocessing.

FIG. 9 is a flowchart illustrating multiple first image quick review andplayback processing.

FIGS. 10A, 10B, 10C, 10D, 10E, 10F, 10G, and 10H are diagramsillustrating display examples where a processing select dialog isdisplayed during a quick review in multiple exposure shooting.

FIG. 11 is a flowchart illustrating one image back processing.

FIG. 12 is a flowchart illustrating save and exit processing.

FIG. 13 is a flowchart illustrating exit without saving processing.

FIG. 14 is a diagram illustrating a display example of anotherpresetting menu screen for multiple exposure shooting.

DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments, features, and aspects of the inventionwill be described in detail below with reference to the drawings.

FIG. 1 is a block diagram illustrating the configuration of a digitalcamera 100, which serves as an imaging apparatus according to anexemplary embodiment of the present invention.

In FIG. 1, a photographic lens 101 is a detachably-attachedinterchangeable lens, which includes a zoom lens and a focus lens.

An autofocus (AF) drive circuit 102 includes a direct-current (DC) motoror a stepping motor, for example. The AF drive circuit 102 changes theposition of a focus lens included in the photographic lens 101 forfocusing under control of a microcomputer 123.

A diaphragm drive circuit 104 drives a diaphragm 103. The microcomputer123 calculates the amount of driving, and the diaphragm drive circuit104 changes an optical aperture value.

A main mirror 105 is a mirror for switching a light flux incident fromthe photographic lens 101 to between a finder side and an image sensor112 side. The main mirror 105 is arranged to reflect the light fluxtoward a finder unit when in a normal condition. When performingphotographing and during a live view display, the main mirror 105 isflipped up and retracted out of the light flux so that the light flux isintroduced to the image sensor 112. The main mirror 105 is configured asa half mirror so that some of the light can be transmitted through acenter area. Some of the light flux is thus transmitted and madeincident on a sensor for focus detection.

A sub mirror 106 is a mirror for reflecting a light flux transmittedthrough the main mirror 105 toward the sensor intended for focusdetection (which is included in a focus detection circuit 109).

A mirror drive circuit 107 drives the main mirror 105 under control ofthe microcomputer 123.

A pentagonal prism 108 constitutes a finder. The finder also includes afocusing screen and an eyepiece lens (not illustrated).

The focus detection circuit 109 is a block intended for focus detection.A sensor for photoelectric conversion is arranged inside the focusdetection circuit 109. The light flux that is transmitted through thecenter area of the main mirror 105 and reflected by the sub mirror 106reaches the sensor for photoelectric conversion. The sensor output canbe calculated to determine a defocus amount for use in focuscalculation. The microcomputer 123 evaluates the result of calculationand instructs the AF drive circuit 102 to drive the focus lens.

A shutter drive circuit 111 drives a focal plane shutter 110. Themicrocomputer 123 controls an opening time of the focal plane shutter110.

Examples of the image sensor 112 include a charge-coupled device (CCD)sensor and a complementary metal oxide semiconductor (CMOS) sensor. Theimage sensor 112 converts an object image formed by the photographiclens 101 into an electrical signal.

An analog-to-digital (A/D) converter 115 converts an analog outputsignal output from the image sensor 112 into a digital signal.

An image signal processing circuit 116 is implemented by logic devicessuch as a gate array. The image signal processing circuit 116 performsvarious types of image signal processing.

A display drive circuit 117 is a drive circuit that causes a displaymember 118 to produce a display.

The display member 118 is a display such as a thin-film transistor (TFT)liquid crystal display and an organic electroluminescence (EL) display.In the present exemplary embodiment, the display member 118 isimplemented as a rear monitor of the digital camera 100.

A memory controller 119 stores unprocessed digital image data input fromthe image signal processing circuit 116 into a buffer memory 122, andstores processed digital image data into a recording medium 120. Thememory controller 119 outputs image data from the buffer memory 122 andthe recording medium 120 to the image signal processing circuit 116. Thememory control 119 can output an image or images stored in the recordingmedium 120 through an external interface 121, which is connectable to acomputer.

The recording medium 120 is a removable recording medium such as amemory card. The recording medium 120 may be a built-in recording mediumof the digital camera 100. A plurality of recording media may be used.

The external interface 121 is an interface for establishing connectionwith an external device such as a computer by wired or wirelesscommunications.

The buffer memory 122 is a memory for temporarily retaining image data.Various images used in the process of multiple exposure shooting arealso stored in the buffer memory 122.

The image signal processing circuit 116 performs filter processing,color conversion processing, and gamma processing on a digitized imagesignal to generate development data. The image signal processing circuit116 also performs Joint Photographic Experts Group (JPEG) or othercompressing processing and outputs the result to the memory controller119.

The image signal processing circuit 116 can add two or more pieces ofdevelopment data on the buffer memory 122, generate high-precision datawith increased gradation bits from development data, or simultaneouslyperform both the processes, and write the result back to the buffermemory 122. The image signal processing circuit 116 can also output animage signal from the image sensor 112 and/or an image signal reverselyinput from the memory controller 119 to the display member 118 throughthe display drive circuit 117. The image signal processing circuit 116switches such functions based on an instruction from the microcomputer123. The image signal processing circuit 116 can output information tothe microcomputer 123 if needed. Examples of the information includeexposure information on the signal of the image sensor 112 andinformation on white balance. Based on such pieces of information, themicrocomputer 123 issues instructions as to white balance and a gainadjustment. In a continuous shooting operation, shot data is once storedinto the buffer memory 122 as unprocessed images. The image signalprocessing circuit 116 reads the unprocessed image data through thememory controller 119, and performs image processing and compressionprocessing for continuous shooting. The number of shots in continuousshooting depends on the capacity of the buffer memory 122.

The microcomputer 123 is a main control unit for controlling the entiredigital camera 100. The microcomputer 123 executes various types ofprograms recorded on a nonvolatile memory 130 by using a system memory132 as a work memory.

An operation detection unit 124 detects that an operation member isoperated. If the operation member is operated, the operation detectionunit 124 informs the microcomputer 123 of that state. The microcomputer123 controls various components according to the change of the operationmember. The operation detection unit 124 is capable of detecting theopen/close state of a lid of a slot where the recording medium 120 isaccommodated (hereinafter, referred to as a card lid) and the open/closestate of a battery lid.

An example of the operation member is a release button 10. A switch 1(hereinafter, referred to as SW1) 125 is a switch that is turned ON by ahalf press operation of the release button 10. If the SW1 125 is ON, themicrocomputer 123 performs shooting preparation processes such as an AFoperation and a light metering operation.

A switch 2 (hereinafter, referred to as SW2) 126 is a switch that isturned ON by a full press operation of the release button 10. If the SW2126 is ON, the microcomputer 123 performs an actual shooting process ofcapturing an image and recording the captured image on the recordingmedium 120 as an image file.

A continuous shooting operation is performed while the SW1 125 and theSW2 126 remain ON.

A liquid crystal drive circuit 127 drives an external liquid crystaldisplay member 128 and an in-finder liquid crystal display member 129according to display contents and commands from the microcomputer 123.The external liquid crystal display member 128 and the in-finder liquidcrystal display member 129 display operation statuses and messages byusing characters and/or graphics. The in-finder liquid crystal displaymember 129 includes a not-illustrated backlight such as a light-emittingdiode (LED). The liquid crystal drive circuit 127 also drives the LED.

Parameters such as an International Organization for Standardization(ISO) sensitivity, an image size, and image quality are set in advanceof shooting. The microcomputer 123 can check the remaining capacity ofthe recording medium 120 through the memory controller 119, andcalculate the number of shots available based on predicted value data onan image size according to the set parameters. The number of shotsavailable may be displayed on the display member 118, the externalliquid crystal display member 128, and/or the in-finder liquid crystaldisplay member 129 if needed.

Examples of the nonvolatile memory 130 include an electrically erasableprogrammable read-only memory (EEPROM) and a flash memory. Thenonvolatile memory 130 can retain data even when the digital camera 100is not powered on. A power supply unit 131 provides a necessary powersupply to the foregoing blocks and drive systems.

FIGS. 2A and 2B illustrate external views of the digital camera 100.FIG. 2A is a front perspective view of the digital camera 100. FIG. 2Bis a rear perspective view of the digital camera 100. The frontperspective view illustrates the digital camera 100 with thephotographic lens 101, an interchangeable lens, dismounted.

As illustrated in FIG. 2A, the digital camera 100 has operation membersincluding the release button 10, a main electronic dial 11, an ISOsetting button 12, an exposure compensation button 13, a shooting modedial 14, and an aperture reducing button 15. The aperture reducingbutton 15 is a button for reducing the diaphragm 103 to a set aperturestop value (F value). The user can press the aperture reducing button 15to check the brightness of a captured image through the set apertureduring a live view display in a shooting mode. A live view displayrefers to a continuous display of images being captured by the imagesensor 112 on the display member 118 generally in real time, with themain mirror 105 retracted. Such a display, or a through display, makesthe display member 118 function as an electronic viewfinder. The mainelectronic dial 11 is a rotating operation member. The main electronicdial 11 is used for operations such as increasing and decreasing variousset values including a photographing condition, changing a selected itemwhen selecting various items, and switching images in units of groupswhen in a playback mode.

As illustrated in FIG. 2B, the digital camera 100 has operation membersincluding an information display button 16, a menu button 17, a playbackbutton 18, a delete button 19, a main switch 20, and a set button 21.The digital camera 100 also has a sub electronic dial 22, a zoom-inbutton 23, a zoom-out button 24, and a multi controller 25. The mainswitch 20 is an operation member for powering ON/OFF the digital camera100. The sub electronic dial 22 is a rotating operation member. The subelectronic dial 22 is used for operations such as changing a selecteditem when selecting various items, and switching images to display whenin a playback mode. An eye-side finder unit 26 is an eyepiece unitthrough which the user looks into a viewfinder and views an opticalimage.

Next, a method of setting preset items as to multiple exposure shootingwill be described.

FIGS. 3A and 3B illustrate display examples of a menu screen for makingsettings of the digital camera 100 as to multiple exposure shooting. Amenu screen 300 as to multiple exposure shooting illustrated in FIG. 3Aappears on the display member 118 when the user presses the menu button17 to display a general menu, selects a menu for multiple exposureshooting from the general menu, and confirms the selection.

The menu screen 300 displays menu items 301 to 304. The user can operatethe sub electronic dial 22 to select any of the menu items 301 to 304.When the user presses the set button 21 with any one of the menu itemsselected, a list of setting candidates for the selected menu item isdisplayed. The user can operate the sub electronic dial 22 or make otheroperations to select a desired setting candidate from the displayed listof setting candidates, and press the set button 21 again to confirm andset the selected setting candidate as a set value.

The menu item 301 is a menu item for selecting whether to performmultiple exposure shooting. Either one of two setting candidates “on”and “off” can be selected and set. Hereinafter, the setting of thepresent menu item 301 will be referred to as a multiple exposureshooting necessity setting. The multiple exposure shooting necessitysetting is recorded in the system memory 132 or the nonvolatile memory130. If the multiple exposure shooting necessity setting is changed from“off” to “on” according to a user operation, the digital camera 100starts multiple exposure shooting at the next image capturing. Themultiple exposure shooting necessity setting is automatically changedfrom “on” to “off” under several conditions to be described below, suchas when multiple exposure shooting has reached a predetermined number ofshots and ended. If the menu item 301 is set to “off” according to auser operation in a multiple exposure shooting in-process state to bedescribed below, the digital camera 100 ends the multiple exposureshooting at that point. Here, a multiple combined image file isgenerated if possible.

The menu item 302 is a menu item for selecting the number of images tobe superimposed for a set of multiple exposure shots. The number ofimages can be selected and set from among setting candidates of 2 to 9.If a base image to be described below is not selected, the number ofimages set by the menu item 302 serves as the number of imagespredetermined for multiple exposure shooting. If a base image isselected, the number of images predetermined for multiple exposureshooting is the number of images selected by the menu item 302 minusone. The number of images predetermined for multiple exposure shootingis recorded in the system memory 132. It should be noted that the menuitem 302 is not selectable to change if one or more images have beencaptured by multiple exposure shooting and the multiple exposureshooting is yet to be completed. Such a state will hereinafter bereferred to as a multiple exposure shooting in-process state. In themultiple exposure shooting in-process state, a multiple exposureshooting in-process flag to be described below is set to 1.

The menu item 303 is a menu item for selecting whether an automaticexposure adjustment function needs to be performed in multiple exposureshooting. Either one of two setting candidates “on” and “off” can beselected and set. The present menu item 303 is not selectable to changein the multiple exposure shooting in-process state.

The menu item 304 is a menu item for selecting a base image for multipleexposure shooting. Any one of images recorded on the recording medium120 can be selected and set as a base image. The present menu item 304can be set only when the multiple exposure shooting necessity setting isset at “on” and the digital camera 100 is in a state other than themultiple exposure shooting in-process state. More specifically, a baseimage can be set by the menu item 304 only between when the multipleexposure shooting necessity setting is set at “on” and when the firstimage is captured. If a base image is set, the screen display changes tothat illustrated in FIG. 3B. An image 306 is an image that is selectedas a base image from among images recorded on the recording medium 120.The image signal processing circuit 116 reads a base image from therecording medium 120, converts the base image into development data, andloads the resulting development data into the buffer memory 122. When abase image is selected, the set value of an image size serving as aphotographing condition (the image size of an image or images to becaptured in the subsequent multiple exposure shooting) is set at thesame value as the image size of the base image. The selection of a baseimage makes it possible to perform multiple exposure shooting with animage captured in the past as the first captured image. In the presentexemplary embodiment, images that can be selected as a base image arelimited to images previously captured by the digital camera 100 becausethe image sizes need to be matched. Images other than those captured bythe digital camera 100 may be included as candidates for a base image ifthe images have image sizes that the digital camera 100 can set as aphotographing condition. When multiple exposure shooting ends, thesetting of a base image is cancelled and the digital camera 100 returnsto the state where no base image is selected. A cancel selected imagebutton 305 is a button icon for canceling a selected base image. Whenthe cancel selected image button 305 is selected, the digital camera 100immediately restores the state where no base image is selected.

Referring to FIGS. 4A to 4E, data retained in the buffer memory 122during multiple exposure shooting will be described. Each time an imageis captured, the buffer memory 122 retains up to five pieces of imagedata including development data, high-precision data, multipledevelopment data, display-specific multiple data, and previous imagecapturing time display-specific multiple data.

Development data refers to data that is generated by applyingdevelopment processing such as color processing to an image signalobtained from the image sensor 112 in the image capturing immediatelybefore. The development data can be compressed in the JPEG format togenerate an image file of an original image to be recorded on therecording medium 120.

For the purpose of multiple combination, development data obtained bythe previous image capturing is subjected to the image signal processingcircuit 116 for bit enhancement (hereinafter, precision enhancement).High-precision data refers to the bit-enhanced image data that is addedto high-precision data generated before. The precision enhancement canreduce the possibility that gradations may be saturated by multiplecombination processing. Other processing that facilitates multiplecombination may be applied aside from the precision enhancement.

Multiple development data is high-precision data currently generated(multiple-combined with an image or images obtained before) to whichdevelopment data obtained by the current image capturing is added. Themultiple development data can be compressed in the JPEG format togenerate an image file of a multiple combined image to be recorded onthe recording medium 120.

Display-specific multiple data is data that is generated by reducing andcompressing multiple development data for display purpose. Such data isused to perform multiple quick review (hereinafter, also referred to asQR) and playback processing and multiple first image QR and playbackprocessing to be described below.

Previous image capturing time display-specific multiple data isdisplay-specific multiple data that has been generated by previous imagecapturing. A multiple image combination and a multiple image combinationresult image may refer to an image generated by superimposing,composing, synthesizing, or merging images by way of example and not oflimitation. Multiple image combination and multiple image combinationresult image do not refer to synthesizing a plurality of images that areplaced in a tile-arranged configuration such as is done for a panoramiceffect. Multiple image combination and multiple image combination resultimage may be referred to as multiple-synthesize image,multiple-composite image, multiple image combination image, ormultiple-composite image.

FIGS. 4A to 4E illustrate data retained in the buffer memory 122 inrespective states without a base image.

FIG. 4A illustrates the state of the buffer memory 122 after the firstimage is captured. An image signal A is obtained by the capturing of thefirst image. The image signal A is developed into development data A,which is then retained in the buffer memory 122. Note that none of thehigh-precision data, multiple development data, display-specificmultiple data, and previous image capturing time display-specificmultiple data is generated or stored, and as much free area is reservedin the buffer memory 122. Since as much capacity as needed to storehigh-precision data, multiple development data, display-specificmultiple data, and previous image capturing time display-specificmultiple data is left unused, the capacity may be allocated for otherprocessing so that the other processing can be performed at high speed.Examples of the other processing include face detection processing usinglive view shooting, and contrast AF processing.

FIG. 4B illustrates the state of the buffer memory 122 after the secondimage is captured. An image signal B is obtained by the capturing of thesecond image. The image signal B is developed into development data B,which is then retained in the buffer memory 122. The development data Awhich has been retained since the capturing of the first image isenhanced in precision and retained as high-precision data A (no additionoccurs because there has been no high-precision data retained after thefirst image). The high-precision data A and the development data B aremultiple combined to generate multiple development data A+B, which isthen retained in the buffer memory 122. The multiple development dataA+B is reduced and compressed to generate display-specific multiple dataA+B, which is then retained in the buffer memory 122. There is nodisplay-specific multiple data generated when the first image iscaptured. When the second image is captured, previous image capturingtime display-specific multiple data is thus generated from the imagefile of the first image A recorded on the recording medium 120. Thegenerated previous image capturing time display-specific multiple datais then retained in the buffer memory 122.

FIG. 4C illustrates the state of the buffer memory 122 after the thirdimage is captured. An image signal C is obtained by the capturing of thethird image. The image signal C is developed into development data C,which is then retained in the buffer memory 122. The development data Bwhich has been retained since the capturing of the second image isenhanced in precision. The result is added to the high-precision data A,which has been retained since the capturing of the second image, togenerate high-precision data A+B. The generated high-precision data A+Bis then retained in the buffer memory 122. The high-precision data A+Band the development data C are multiple combined to generate multipledevelopment data A+B+C, which is then retained in the buffer memory 122.The multiple development data A+B+C is reduced and compressed togenerate display-specific multiple data A+B+C, which is then retained inthe buffer memory 122. The display-specific multiple data A+B, which isgenerated when the second image is captured, is retained as previousimage capturing time display-specific multiple data A+B.

FIG. 4D illustrates the state of the buffer memory 122 when the imageobtained by the third image capturing is discarded by multiple QR andplayback processing to be described below. When the image obtained bythe third image capturing is discarded, then the development data C, themultiple development data A+B+C, and the display-specific multiple dataA+B+C are discarded from the buffer memory 122 of the state illustratedin FIG. 4C. The image data that is retained as the previous imagecapturing time display-specific multiple data A+B in FIG. 4C is retainedas display-specific multiple data A+B in FIG. 4D.

FIG. 4E illustrates the state of the buffer memory 122 when the thirdimage is recaptured after the third captured image is discarded. Animage signal D is obtained by the recapturing of the third image (imagecapturing in a multiple exposure shooting mode after acceptance of arecapturing instruction). The image signal D is developed intodevelopment data D, which is then retained in the buffer memory 122. Thehigh-precision data A+B which has been retained since the discard of thethird image is retained unchanged. The high-precision data A+B and thedevelopment data D are multiple combined to generate multipledevelopment data A+B+D, which is then retained in the buffer memory 122.The multiple development data A+B+D is reduced and compressed togenerate display-specific multiple data A+B+D, which is then retained inthe buffer memory 122. The display-specific multiple data A+B which hasbeen retained since the discard of the third image is retained asprevious image capturing time display-specific multiple data A+B.

Next, data used in the processing of multiple exposure shooting will bedescribed. The processing of multiple exposure shooting is executed byusing the following variables:

-   -   Multiple exposure shooting necessity setting: Can be set to        either “on” or “off.” The set value is recorded in the        nonvolatile memory 130 or the system memory 132. The state “on”        indicates a multiple exposure shooting mode.    -   Multiple exposure shooting in-process flag: A variable that        indicates whether multiple exposure shooting is in process. This        variable is recorded in the system memory 132. If the multiple        exposure shooting necessity setting is set at “on” and one or        more images are captured, the multiple exposure shooting        in-process flag is 1 (multiple exposure shooting in-process        state). If multiple exposure shooting ends, the multiple        exposure shooting in-process flag is “0”. Whether to perform        normal quick review processing or multiple quick review        processing is determined based on this flag.    -   Number of images predetermined for multiple exposure shooting: A        value that indicates the number of times of multiple exposure        shooting to be performed (hereinafter, referred to as a set of        multiple exposure shots) for generating a multiple combined        image. This value is recorded in the system memory 132. If no        base image is set, the number of images predetermined for        multiple exposure shooting is the number of images set via the        menu item 302 illustrated in FIG. 3. If a base image is set, the        number of images predetermined for multiple exposure shooting is        the number of images set via the menu item 302 illustrated in        FIG. 3 minus one.    -   Number of images captured for multiple exposure shooting: A        value that indicates the number of images captured so far for a        set of multiple exposure shots. This value is recorded in the        system memory 132. If the number of images captured for multiple        exposure shooting reaches the number of images predetermined for        multiple exposure shooting, a set of multiple exposure shots        ends. The multiple exposure shooting processing is thus        completed.

In the multiple exposure shooting in-process state, information thatindicates the storage location of each original image captured so far bya set of multiple exposure shots on the recording medium 120 is recordedin the system memory 132 as written file information. If there is aplurality of recording media to record images on, information thatspecifies the storing recording medium is also recorded.

FIG. 5 is a flowchart illustrating multiple exposure shooting modeprocessing. The processing illustrated in FIG. 5 is implemented by aprogram recorded in the nonvolatile memory 130 being loaded into thesystem memory 132 and executed by the microcomputer 123. The processingillustrated in FIG. 5 starts when the multiple exposure shootingnecessity setting is set to “on.”

In step S501, the microcomputer 123 determines whether the SW2 is ON. Ifthe SW2 is ON (YES in step S501), the microcomputer 123 proceeds to stepS502. If the SW2 is not ON (NO in step S501), the microcomputer 123proceeds to step S507.

In step S502, the microcomputer 123 performs multiple exposure shootingprocessing. The multiple exposure shooting processing will be describedin detail below with reference to FIG. 6.

In step S503, the microcomputer 123 refers to the system memory 132 anddetermines whether the number of images captured for multiple exposureshooting is “1”. In other words, the microcomputer 123 determineswhether the first image for a set of multiple exposure shots is capturedby the multiple exposure shooting processing performed in step S502. Ifthe number of images captured for multiple exposure shooting is “1” (YESin step S503), the microcomputer 123 proceeds to step S504. In stepS504, the microcomputer 123 sets a multiple exposure shooting in-processflag of “1” in the system memory 132. If in step S503 the number ofimages captured for multiple exposure shooting is determined to be not“1” (NO in step S503) or after the multiple exposure shooting in-processflag is set to “1” in step S504, the microcomputer 123 proceeds to stepS505.

In step S505, the microcomputer 123 determines whether the number ofimages captured for multiple exposure shooting retained in the systemmemory 132 is equal to the number of images predetermined for multipleexposure shooting. If the two numbers are equal (YES in step S505), aset of multiple exposure shots has been completed. In step S506, themicrocomputer 123 performs save and exit processing, and then ends themultiple exposure shooting mode processing. The save and exit processingwill be described below with reference to FIG. 12.

In step S507, the microcomputer 123 determines whether the playbackbutton 18 is pressed (whether there is an instruction to enter aplayback mode). If the playback button 18 is pressed (YES in step S507),the microcomputer 123 proceeds to step S508. If the playback button 18is not pressed (NO in step S507), the microcomputer 123 proceeds to stepS514.

In step S508, the microcomputer 123 refers to the system memory 132 anddetermines whether the multiple exposure shooting in-process flag is “1”(whether in the multiple exposure shooting in-process state). If themultiple exposure shooting in-process flag is “1” (YES in step S508),the microcomputer 123 proceeds to step S510. If the multiple exposureshooting in-process flag is not “1” (NO in step S508), the microcomputer123 proceeds to step S509.

In step S509, the microcomputer 123 performs normal playback modeprocessing. In the normal playback mode processing, the microcomputer123 performs playback processing including a single image display, amultiple display, image advancing, delete, and attaching an attribute.The playback mode processing is targeted for all images that arerecorded on the recording medium 120 and reproducible by the digitalcamera 100.

In step S510, the microcomputer 123 determines whether a base image isset. If no base image is set (NO in step S510), the microcomputer 123proceeds to step S511. If a base image is set (YES in step S510), themicrocomputer 123 proceeds to step S513.

In step S511, the microcomputer 123 determines whether the number ofimages captured for multiple exposure shooting recorded in the systemmemory 132 is greater than or equal to “2”. If the number is determinedto be greater than or equal to “2” (YES in step S511), the microcomputer123 proceeds to step S513. If the number is less than “2” (NO in stepS511), the microcomputer 123 proceeds to step S512. Since the multipleexposure shooting in-process flag is “1”, that the number of imagescaptured for multiple exposure shooting is less than “2” means that thenumber of images captured for multiple exposure shooting is “1”.

In step S512, the microcomputer 123 performs multiple first image QR andplayback processing. The multiple first image QR and playback processingis display processing intended to check an image that has been acquiredafter entry to a multiple exposure shooting mode, and to check how theimage is multiple combined. None of the images captured before the entryto the multiple exposure shooting mode is displayed, except a baseimage. The multiple first image QR and playback processing will bedescribed below with reference to FIG. 9.

In step S513, the microcomputer 123 performs multiple QR and playbackprocessing. The multiple QR and playback processing is displayprocessing to check images that have been acquired after entry to themultiple exposure shooting mode, and to check how the images aremultiple combined. None of images captured before the entry to themultiple exposure shooting mode is displayed, except a base image. Themultiple QR and playback processing will be described below withreference to FIG. 8.

In step S514, the microcomputer 123 refers to the system memory 132 anddetermines whether the multiple exposure shooting in-process flag is“1”. If the multiple exposure shooting in-process flag is “1” (YES instep S514), the microcomputer 123 proceeds to step S515. If the multipleexposure shooting in-process flag is not “1” (NO in step S514), themicrocomputer 123 proceeds to step S517.

In step S515, the microcomputer 123 determines whether an interruptiveevent has occurred. The interruptive event refers to an event on whichthe multiple exposure shooting mode is to be interrupted. Examplesinclude the following:

-   -   An event that changes the multiple exposure shooting necessity        setting to “off” according to a user operation.    -   A user operation on the main switch 20, opening of the card lid,        and opening of the battery lid. An event that turns off the        power, such as expiration of an automatic power-off time.    -   An event that prevents continuation of multiple exposure        shooting depending on conditions of shooting settings.        If an interruptive event has occurred (YES in step S515), the        microcomputer 123 proceeds to step S516. If no such event has        occurred (NO in step S515), the microcomputer 123 proceeds to        step S517.

In step S516, the microcomputer 123 performs the save and exitprocessing. The save and exit processing will be described below withreference to FIG. 12.

In step S517, the microcomputer 123 refers to the multiple exposureshooting necessity setting stored in the system memory 132 or thenonvolatile memory 130, and determines whether the multiple exposureshooting is set at “on.” If the multiple exposure shooting is set at“on” (YES in step S517), the microcomputer 123 proceeds to step S501 torepeat the multiple exposure shooting mode processing. If the multipleexposure shooting is set at “off” (NO in step S517), the microcomputer123 ends the multiple exposure shooting mode processing.

FIG. 6 is a flowchart illustrating the multiple exposure shootingprocessing in step S502 illustrated in FIG. 5 described above. Theprocessing illustrated in FIG. 6 is implemented by a program recorded inthe nonvolatile memory 130 being loaded into the system memory 132 andexecuted by the microcomputer 123.

In step S601, the microcomputer 123 controls exposure. When the exposureis completed, then in step S602, the microcomputer 123 performs controlto read an image signal accumulated in the image sensor 112.

In step S603, the microcomputer 123 instructs the image signalgeneration circuit 116 to generate development data from the imagesignal read in step S602. As illustrated in FIGS. 4A to 4E, thegenerated development data is stored in the buffer memory 122.

In step S604, the microcomputer 123 causes the image signal processingcircuit 116 to compress the development data generated in step S603. Instep S605, the microcomputer 123 records the result on the recordingmedium 120 as an image file (first recording control). The image filecontains a single original image, not a combined one. In step S606, themicrocomputer 123 adds information indicating the storage location ofthe image file recorded in step S605 to written file informationretained in the system memory 132. Instead of or in addition to theinformation indicating the storage location of the image file, themicrocomputer 123 may record information that identifies the image file(such as a file name). The microcomputer 123 adds “1” to the number ofimages captured for multiple exposure shooting retained in the systemmemory 132.

In step S607, the microcomputer 123 determines whether a base image isset. If there is a base image (YES in step S607), the microcomputer 123proceeds to step S608. If no base image is set (NO in step S607), themicrocomputer 123 proceeds to step S611.

In step S608, the microcomputer 123 refers to the system memory 132 anddetermines whether the number of images captured for multiple exposureshooting is greater than or equal to “2”. If the number is less than“2”, i.e., the number of captured images is only one which results fromthe current image capturing (NO in step S608), the microcomputer 123proceeds to step S609. If the number is greater than or equal to “2”(YES in step S608), the microcomputer 123 proceeds to step S610.

In step S609, the microcomputer 123 reads the base image from therecording medium 120 and acquires development data of the base image.The microcomputer 123 enhances the precision of the development data ofthe base image by using the image signal processing circuit 116, andstores the resulting high-precision data into the buffer memory 122. Inother words, the processing is performed with the base image as an imagesignal A obtained by the capturing of the first image in FIG. 4B andwith the image data acquired by the current image capturing in step S602as an image signal B obtained by the capturing of the second image inFIG. 4B.

In step S610, the microcomputer 123 enhances the precision of thedevelopment data obtained by the previous image capturing by using theimage signal processing circuit 116. The microcomputer 123 adds theresult to high-precision data generated before to generatehigh-precision data, and stores the high-precision data into the buffermemory 122. In terms of the example illustrated in FIGS. 4A to 4E, suchan operation translates as follows: When the third image is captured inFIG. 4C, development data B obtained by the capturing of the secondimage is enhanced in precision. The result is added to high-precisiondata A that is generated when the second image is captured, wherebyhigh-precision data A+B is generated. The high-precision data A+B isstored into the buffer memory 122.

In step S611, the microcomputer 123 refers to the system memory 132 anddetermines whether the number of images captured for multiple exposureshooting is greater than or equal to “2”. If the number is determined tobe greater than or equal to “2” (YES in step S611), the microcomputer123 proceeds to step S612. If the number is less than “2”, i.e., thenumber of captured images is only one, which results from the currentimage capturing (NO in step S611), the microcomputer 123 proceeds tostep S618. If in step S611 the number of images captured for multipleexposure shooting is determined to be only one, which results from thecurrent image shooting (NO in step S611), the buffer memory 122 is inthe state illustrated in FIG. 4A.

In step S612, the microcomputer 123 determines whether the number ofimages captured for multiple exposure shooting is “2”. If the number isnot “2”, i.e., is three or greater (NO in step S612), the microcomputer123 proceeds to step S610. If the number is “2” (YES in step S612), themicrocomputer 123 proceeds to step S613.

In step S613, the microcomputer 123 enhances the precision of thedevelopment data obtained by the previous image capturing by using theimage signal processing circuit 116, thereby generating high-precisiondata. The microcomputer 123 stores the high-precision data into thebuffer memory 122. In terms of the example illustrated in FIGS. 4A to4E, such an operation translates as follows. Development data A obtainedby the capturing of the first image is enhanced in precision when thesecond image is captured in FIG. 4B. The result is stored into thebuffer memory 122 as high-precision data A.

In step S614, the microcomputer 123 multiple combines high-precisiondata generated in any one of steps S609, S610, and S613 with thedevelopment data of the current captured image, generated in step S603,by using the image signal processing circuit 116. The microcomputer 123stores the generated multiple combined image into the buffer memory 122as multiple development data.

In step S615, the microcomputer 123 reduces and compresses thehigh-precision data generated in step S614 by using the image signalprocessing circuit 116. The microcomputer 123 stores the result into thebuffer memory 122 as display-specific multiple data.

In step S616, the microcomputer 123 determines whether a quick review(QR) is set to be made. Whether to make a QR immediately after imagecapturing may be set in advance according to a user operation. If a QRis set to be made (YES in step S616), the microcomputer 123 proceeds tostep S617. In step S617, the microcomputer 123 performs the multiple QRand playback processing. The multiple QR and playback processing will bedescribed below with reference to FIG. 8. If in step S616 a QR is setnot to be made (NO in step S616) or after the processing in step S617 iscompleted, the microcomputer 123 ends the multiple exposure shootingprocessing. The microcomputer 123 then proceeds to step S503 illustratedin FIG. 5 described above.

In step S618, the microcomputer 123 determines whether a quick review(QR) is set to be made. If a QR is set to be made (YES in step S618),the microcomputer 123 proceeds to step S619. In step S619, themicrocomputer 123 performs the multiple first image QR and playbackprocessing. The multiple first image QR and playback processing will bedescribed below with reference to FIG. 9. If in step S618 a QR is setnot to be made (NO in step S618) or after the processing in step S619 iscompleted, the microcomputer 123 ends the multiple exposure shootingprocessing. The microcomputer 123 then proceeds to step S503 illustratedin FIG. 5 described above.

FIGS. 7A and 7B illustrate display examples of an initial display screento be displayed on the display member 118 for a quick review in multipleexposure shooting (display control). FIGS. 7A and 7B each illustrate adisplay example where the number of images to be superimposed formultiple exposure shooting is set at “3” via the menu item 302illustrated in FIG. 3 described above, and no base image is set via themenu item 304.

FIG. 7A illustrates an initial display screen that is displayed for aquick review immediately after the capturing of the first image for aset of multiple exposure shots. Such a screen is initially displayed inthe multiple first image QR and playback processing illustrated in FIG.9 to be described below. A display item 701 includes an icon thatindicates that the image is the one obtained by multiple exposureshooting. The display item 701 also includes an indication that thereare two images left to reach the number of images predetermined formultiple exposure shooting. A display item 702 is a guide displayindicating that the delete button 19 can be pressed to display aprocessing select dialog to be described below. An image 703 is the onethat is not multiple combined because only one image has been captured.The image 703 is based on an image file read from the recording medium120.

FIG. 7B illustrates an initial display screen that is displayed for aquick review immediately after the capturing of the second image for aset of multiple exposure shots. Such a screen is initially displayed inthe multiple QR and playback processing illustrated in FIG. 8 to bedescribed below. A display item 704 expresses a meaning similar to thatof the display item 701 in FIG. 7A. The display item 704 indicates thatthere is one image left, one fewer, to reach the number of imagespredetermined for multiple exposure shooting. An image 705 is a multiplecombined image of the first image and the currently-captured, second,image. The image 705 displays the display-specific multiple data A+B inFIG. 4B

FIG. 8 is a flowchart illustrating the multiple QR and playbackprocessing in step S513 illustrated in FIG. 5 and step S617 illustratedin FIG. 6 described above. The processing illustrated in FIG. 8 isimplemented by a program recorded in the nonvolatile memory 130 beingloaded into the system memory 132 and executed by the microcomputer 123.

In step S801, the microcomputer 123 starts counting (starts a timer) thetime of a quick review (for example, two seconds). Such processing isnot performed if a quick review time is set at HOLD (no automaticcancellation) or if the playback button 18 has been pressed to enter theprocessing illustrated in FIG. 8 (i.e., when in the playback modeprocessing).

In step S802, the microcomputer 123 displays display-specific multipledata illustrated in FIGS. 4A to 4E on the display member 118. A displayexample is illustrated in FIG. 7B described above. The user can view thedisplay-specific multiple data to check a multiple combined image thatis to be generated from images obtained by image capturing so far. Morespecifically, the user can check a multiple combined image (first image)made of a number (first number) of images including an image or imagesas many as the number of images captured for multiple exposure shootingat this point in time and a base image if any.

In step S803, the microcomputer 123 determines whether a predeterminedquick view time has elapsed from the clocking of step S801. If thepredetermined time has elapsed (YES in step S803), the microcomputer 123ends the multiple QR and playback processing and returns to the multipleexposure shooting mode processing illustrated in FIG. 5. If thepredetermined time has not elapsed yet (NO in step S803), themicrocomputer 123 proceeds to step S804. The processing in step S803 isnot performed if the quick review time is set to HOLD (no automaticcancellation) or if the playback button 18 has been pressed to enter theprocessing illustrated in FIG. 8 (i.e., when in the playback modeprocessing).

In step S804, the microcomputer 123 determines whether the SW1 is ON andwhether the playback button 18 is pressed. If the SW1 is determined tobe ON or the playback button 18 is determined to be pressed (YES in stepS804), the microcomputer 123 ends the multiple QR and playbackprocessing and returns to the multiple exposure shooting mode processingillustrated in FIG. 5. If not (NO in step S804), the microcomputer 123proceeds to step S805.

In step S805, the microcomputer 123 determines whether the delete button19 is pressed. If the delete button 19 is determined to be pressed (YESin step S805), the microcomputer 123 proceeds to step S806. If thedelete button 19 is determined to be not pressed (NO in step S805), themicrocomputer 123 returns to step S803 and repeats the foregoingprocessing.

In step S806, the microcomputer 123 ends counting time and clears thetimer if the quick review time has started being counted in step S801.

In step S807, the microcomputer 123 displays a processing select dialogon the display member 118. FIG. 10A illustrates a display example of theprocessing select dialog. A processing select dialog 1005 is displayedas superimposed on a display of display-specific multiple data 705. Areturn to previous screen icon 1001, a one image back icon 1002, a saveand exit icon 1003, and an exit without saving icon 1004 are displayedin a lower part of the processing select dialog 1005. A description texton one of the icons 1001 to 1004 that is currently selected by a selectframe is displayed in an upper part of the processing select dialog1005. The select frame can be moved to an arbitrary icon according to anoperation on the sub electronic dial 22. For an initial state, in stepS807, the microcomputer 123 displays the processing select dialog 1005with the return to previous screen icon 1001 selected by the selectframe. Having displayed the processing select dialog 1005, themicrocomputer 123 proceeds to step S810.

In step S810, the microcomputer 123 determines whether the set button 21is pressed to make a confirmation operation with the return to previousscreen icon 1001 selected. If a confirmation operation is determined tobe made with the return to previous screen icon 1001 selected (YES instep S810), then in step S811, the microcomputer 123 dismisses theprocessing select dialog to restore the display illustrated in FIG. 7B.The microcomputer 123 then returns to step S803 to repeat theprocessing. If no such confirmation operation is determined to be made(NO in step S810), the microcomputer 123 proceeds to step S812.

In step S812, the microcomputer 123 determines whether the one imageback icon 1002 is selected by the select frame. If the one image backicon 1002 is selected (YES in step S812), the microcomputer 123 proceedsto step S813. If not (NO in step S812), the microcomputer 123 proceedsto step S816. In step S813, the microcomputer 123 displays previousimage capturing time display-specific multiple data stored in the buffermemory 122, illustrated in FIGS. 4A to 4E, on the display member 118. Adisplay example is illustrated in FIG. 10B. An image 706 representsprevious image capturing time display-specific multiple data. In theexample illustrated in FIG. 10B, two images have been captured for a setof multiple exposure shots when the display is moved one image back. Theimage 706 thus shows a non-multiple image including only the firstimage. If three or more images have been captured when a display ismoved one image back, then the user can check a multiple combined imageexcluding the image captured immediately before (last captured image).More specifically, the user can check a multiple combined image (secondimage) made of a number (second number) of images including images asmany as the number of images captured for multiple exposure shooting atthis point in time and a base image if any (first number), excluding thelast captured image. In such a way, according to an exemplary embodimentof the present invention, a multiple combined image (image 706)excluding the last captured image and a multiple combined image (image705) including the last captured image can be switched for displayduring a quick review or in a playback mode. Such a switched displayallows the user to easily compare the two images and determine whetherthe immediately previous image is a satisfactory one as an image to bemultiple combined. If the immediately previous image is notsatisfactory, the user can discard the immediately previous image andcontinue multiple exposure processing from one image back.

In step S814, the microcomputer 123 determines whether the set button 21is pressed to make a confirmation operation with the one image back icon1002 selected (in other words, whether a recapturing instruction isgiven). If a confirmation operation is determined to be made with theone image back icon 1002 selected (YES in step S814), the microcomputer123 proceeds to step S815. If not (NO in step S814), the microcomputer123 proceeds to step S816.

In step S815, the microcomputer 123 performs one image back processing.The one image back processing will be described below with reference toFIG. 11. Completing the one image back processing, the microcomputer 123ends the multiple QR and playback processing and returns to the multipleexposure shooting mode processing illustrated in FIG. 5.

In step S816, the microcomputer 123 determines whether the save and exiticon 1003 is selected by the select frame. If the save and exit icon1003 is selected (YES in step S816), the microcomputer 123 proceeds tostep S817. If not (NO in step S816), the microcomputer 123 proceeds tostep S820. In step S817, the microcomputer 123 displays display-specificmultiple data stored in the buffer memory 122, illustrated in FIGS. 4Ato 4E, on the display member 118. A display example is illustrated inFIG. 10C. The image 705 displays the display-specific multiple data. Theuser views the image 705. If the multiple combined image generated fromthe images obtained by multiple exposure shooting so far issatisfactory, the microcomputer 123 may generate and save a multiplecombined image and end the multiple exposure shooting.

In step S818, the microcomputer 123 determines whether the set button 21is pressed to make a confirmation operation with the save and exit icon1003 selected. If a confirmation operation is determined to be made withthe save and exit icon 1003 selected (YES in step S818), themicrocomputer 123 proceeds to step S819. If not (NO in step S818), themicrocomputer 123 proceeds to step S820.

In step S819, the microcomputer 123 performs the save and exitprocessing. The save and exit processing will be described below withreference to FIG. 12. Completing the save and exit processing, themicrocomputer 123 ends the multiple QR and playback processing. Themicrocomputer 123 ends the processing in the multiple exposure shootingmode without returning to the multiple exposure shooting mode processingillustrated in FIG. 5, and enters a normal shooting mode.

In step S820, the microcomputer 123 determines whether the exit withoutsaving icon 1004 is selected by the select frame. If the exit withoutsaving icon 1004 is selected (YES in step S820), the microcomputer 123proceeds to step S821. If not (NO in step S820), the microcomputer 123proceeds to step S808. In step S821, the microcomputer 123 displaysdisplay-specific multiple data stored in the buffer memory 122,illustrated in FIGS. 4A to 4E, on the display member 118. A displayexample is illustrated in FIG. 10D. The image 705 displaysdisplay-specific multiple data. The user views the image 705. If themultiple combined image generated from images obtained by multipleexposure shooting so far is not satisfactory on the whole, the user maydiscard all the images captured so far for the set of multiple exposureshots and end the multiple exposure shooting.

In step S822, the microcomputer 123 determines whether the set button 21is pressed to make a confirmation operation with the exit without savingicon 1004 selected. If a confirmation operation is determined to be madewith the exit without saving icon 1004 selected (YES in step S822), themicrocomputer 123 proceeds to step S823. If not (NO in step S822), themicrocomputer 123 proceeds to step S808.

In step S823, the microcomputer 123 performs exit without savingprocessing. The exit without saving processing will be described belowwith reference to FIG. 13. Completing the exit without savingprocessing, the microcomputer 123 ends the multiple QR and playbackprocessing. The microcomputer 123 ends the processing in the multipleexposure shooting mode without returning to the multiple exposureshooting mode processing illustrated in FIG. 5, and enters the normalshooting mode.

In step S808, the microcomputer 123 determines whether the return toprevious screen icon 1001 is selected by the select frame. If the returnto previous screen icon 1001 is selected (YES in step S808), themicrocomputer 123 proceeds to step S809. If not (NO in step S808), themicrocomputer 123 proceeds to step S812. In step S809, the microcomputer123 displays display-specific multiple data stored in the buffer memory122, illustrated in FIGS. 4A to 4E, on the display member 118. A displayexample is illustrated in FIG. 10A described above.

Note that in the initial display in step S802 illustrated in FIG. 8, thedisplay member 118 displays display-specific multiple data. Instead, thedisplay member 118 may display a non-multiple captured image that iscaptured immediately before. Processing of selecting and switching todisplay display-specific multiple data and a non-multiple captured imagemay be added.

FIG. 9 is a flowchart illustrating the multiple first image QR andplayback processing in step S512 illustrated in FIG. 5 and step S619illustrated in FIG. 6 described above. The processing illustrated inFIG. 9 is implemented by a program recorded in the nonvolatile memory130 being loaded into the system memory 132 and executed by themicrocomputer 123.

Step S901 is similar to step S801 illustrated in FIG. 8 described above.Description thereof will thus be omitted.

In step S902, the microcomputer 123 decodes compressed data on the imagefile of an image that is captured immediately before, recorded on therecording medium 120, and displays the resultant on the display member118. A display example is illustrated in FIG. 7A described above. Themultiple first image QR and playback processing illustrated in FIG. 9deals with a situation where there is no base image and only one imagehas been captured by multiple exposure shooting. The buffer memory 122stores no display-specific multiple data. The microcomputer 123 thendisplays the image 703 based on an image file read from the recordingmedium 120.

The processing in steps S903 to S907 and S910 to S912 is similar to theprocessing in steps S803 to S807 and S810 to S812 illustrated in FIG. 8described above, respectively. Description thereof will thus be omitted.FIG. 10E illustrates a display example in step S907.

In step S913, the microcomputer 123 causes the display member 118 todisplay a black image since the buffer memory 122 stores no previousimage capturing time display-specific multiple data. A display exampleis illustrated in FIG. 10F. Such a display can inform the user that,after one image back, there is no image obtained by multiple exposureshooting. Other displays may be used instead of a black image. A warningsuch as “No image to display” may be displayed. An alternative image tothe black image may be a monotone image in order to indicate that theimage is not a captured one.

The processing in steps S914 to S916 is similar to the processing insteps S814 to S816 illustrated in FIG. 8 described above, respectively.Description thereof will thus be omitted.

In step S917, the buffer memory 122 stores no display-specific multipledata. The microcomputer 123 then decodes compressed data on an imagefile of an image that is captured immediately before, recorded on therecording medium 120, and displays the result on the display member 118.A display example is illustrated in FIG. 10G.

The processing in steps S918 to S920 is similar to the processing insteps S818 to S820 illustrated in FIG. 8 described above, respectively.Description thereof will thus be omitted.

In step S921, the buffer memory 122 stores no display-specific multipledata. The microcomputer 123 then decodes compressed data on an imagefile of an image that is captured immediately before, recorded on therecording medium 120, and displays the result on the display member 118.A display example is illustrated in FIG. 10H.

The processing in steps S922, S923, and S908 is similar to theprocessing in steps S822, S823, and S808 illustrated in FIG. 8 describedabove, respectively. Description thereof will thus be omitted.

In step S921, the buffer memory 122 stores no display-specific multipledata. The microcomputer 123 then decodes compressed data on an imagefile of an image that is captured immediately before, recorded on therecording medium 120, and displays the result on the display member 118.

FIG. 11 is a flowchart illustrating the one image back processing instep S815 illustrated in FIG. 8 and step S915 illustrated in FIG. 9described above. The processing illustrated in FIG. 11 is implemented bya program recorded in the nonvolatile memory 130 being loaded into thesystem memory 132 and executed by the microcomputer 123.

In step S1101, the microcomputer 123 refers to written file informationstored in the system memory 132. The microcomputer 123 searches for animage file of an image captured immediately before, recorded on therecording medium 120, and deletes the image file.

In step S1102, the microcomputer 123 deletes information on the imagefile deleted in step S1101 from the written file information stored inthe system memory 132, thereby updating the written file information.

In step S1103, the microcomputer 123 subtracts “1” from the number ofimages captured for multiple exposure shooting retained in the systemmemory 132.

In step S1104, the microcomputer 123 determines whether the number ofimages captured for multiple exposure shooting retained in the systemmemory 132 is “0”. If the number is determined to be not “0” (NO in stepS1104), the microcomputer 123 proceeds to step S1105. If the number isdetermined to be “0” (YES in step S1104), the microcomputer 123 proceedsto step S1106.

In step S1105, the microcomputer 123 discards development data, multipledevelopment data, and previous image capturing time display-specificmultiple data from the buffer memory 122, and ends the one image backprocessing. Such an operation corresponds to changing the state of thebuffer memory 122 from the state illustrated in FIG. 4C to thatillustrated in FIG. 4D described above. In the state illustrated in FIG.4D, high-precision data A+B remains in the buffer memory 122. A thirdimage can thus be recaptured to continue multiple exposure shooting fromthe previous result of multiple exposure shooting. Display-specificmultiple data A+B also remains in the buffer memory 122. After therecapturing of the third image, the display-specific multiple data A+Bis retained as previous image capturing time display-specific multipledata A+B, so that the “one image back” processing can be performedagain.

In step S1106, the microcomputer 123 discards development data from thebuffer memory 122. Such an operation corresponds to discarding thedevelopment data in the state illustrated in FIG. 4A.

In step S1107, the microcomputer 123 resets the multiple exposureshooting in-process flag retained in the system memory 132 to “0”, andends the one image back processing. Although the buffer memory 122contains no image data, the multiple exposure shooting mode processingitself is not terminated here. Multiple exposure shooting can thus becontinued from the first image without performing presetting formultiple exposure shooting again.

FIG. 12 is a flowchart illustrating the save and exit processing in stepS819 illustrated in FIG. 8 and step S919 illustrated in FIG. 9 describedabove. The processing illustrated in FIG. 12 is implemented by a programrecorded in the nonvolatile memory 130 being loaded into the systemmemory 132 and executed by the microcomputer 123.

In step S1201, the microcomputer 123 determines whether the number ofimages captured for multiple exposure shooting retained in the systemmemory 132 is greater than or equal to “2”. If the number is greaterthan or equal to “2” (YES in step S1201), the microcomputer 123 proceedsto step S1202. If the number is less than “2” (NO in step S1201), themicrocomputer 123 proceeds to step S1206.

In step S1202, the microcomputer 123 compresses multiple developmentdata stored in the buffer memory 122 to generate an image file.

In step S1203, the microcomputer 123 generates an image file of amultiple combined image from the multiple development data compressed instep S1202. An example of the generated image file is a JPEG file. Themicrocomputer 123 may refer to written file information retained in thesystem memory 132, and record information that identifies the originalimages of the multiple combined image into a header of the image file ofthe multiple combined image as attribute information. The microcomputer123 may store such information into a different area in association withthe image file.

In step S1204, the microcomputer 123 records the image file of themultiple combined image generated in step S1203 on the recording medium120 (second recording control).

In step S1205, the microcomputer 123 performs multiple exposure shootinginitialization processing. In the initialization processing, themicrocomputer 123 discards all pieces of image data recorded in thebuffer memory 122. The microcomputer 123 resets the number of imagespredetermined for multiple exposure shooting and the number of imagescaptured for multiple exposure shooting recorded in the system memory132. The microcomputer 123 changes the multiple exposure shootingnecessity setting to “off.” The microcomputer 123 resets the multipleexposure shooting in-process flag retained in the system memory 132 to“0”. The microcomputer 123 deletes all the contents of written fileinformation retained in the system memory 132. Completing the processingin step S1205, the microcomputer 123 ends the save and exit processing.

In step S1206, the microcomputer 123 determines whether the number ofimages captured for multiple exposure shooting retained in the systemmemory 132 is “1”. If the number is “1” (YES in step S1206), themicrocomputer 123 proceeds to step S1207. If the number is not “1”,i.e., is “0” (NO in step S1206), the microcomputer 123 proceeds to stepS1205.

In step S1207, the microcomputer 123 determines whether a base image isset. If a base image is set (YES in step S1207), the microcomputer 123proceeds to step S1202. In step S1202, the microcomputer 123 generatesan image file of a multiple combined image and records the image file onthe recording medium 120. If no base image is set (NO in step S1207),the microcomputer proceeds to step S1208.

In step S1208, only one image has been captured for a set of multipleexposure shots and there is no base image. In such a situation, thegeneration of a multiple combined image produces substantially nosuperimposition and results in substantially the same image as the onlyone image. The microcomputer 123, therefore, displays a warning that nomultiple combined image is generated in the absence of superimposition.The microcomputer 123 also displays on the display member 118 a userinterface (UI) for accepting a selection whether to delete the writtenoriginal image file.

In step S1209, the microcomputer 123 determines whether the UI displayedin step S1208 has accepted an instruction from the user via an operationmember, the instruction instructing to delete the written originalimage. If the delete instruction has been received (YES in step S1209),the microcomputer 123 proceeds to step S1210. If no such deleteinstruction has been received (NO in step S1209), the microcomputer 123proceeds to step S1211.

In step S1210, the microcomputer 123 refers to written file informationretained in the system memory 132, and deletes the image file of theoriginal image that is captured in the multiple exposure shooting modeand recorded on the recording medium 120. The microcomputer 123 alsodeletes information on the deleted image file from the written fileinformation.

In step S1211, the microcomputer 123 displays a screen for receiving aselection whether to register the written original image as the firstimage to be displayed on a base image select screen when performingpresetting for multiple exposure shooting next time (selectionacceptance). The microcomputer 123 then determines whether aninstruction to register the written original image as the first image tobe displayed on the base image select screen next time is received fromthe user via an operation member. If the instruction is determined to bereceived (YES in step S1211), the microcomputer 123 proceeds to stepS1212. If the instruction is determined to be not received (NO in stepS1211), the microcomputer 123 proceeds to step S1205.

In step S1212, the microcomputer 123 registers the written originalimage as the first image to be displayed on the base image select screenwhen performing presetting for multiple exposure shooting next time. Asa result, the only image captured in the multiple exposure shooting thatis interrupted by the present processing is displayed as the firstcandidate for a base image when setting a base image from the menu item304 illustrated in FIG. 3 next time. For example, suppose that multipleexposure shooting is started, an image is captured, and the multipleexposure shooting is once ended for the purpose of image capturing otherthan the multiple exposure shooting. The processing in step S1212 canreduce the user's operation burden when resuming the multiple exposureshooting at where it ended the last time.

Completing the processing in step S1212, the microcomputer 123 proceedsto step S1205. In step S1205, the microcomputer 123 performs themultiple exposure shooting initialization processing, and ends the saveand exit processing.

According to the processing illustrated in FIG. 12, multiple exposureshooting may be ended without a base image and with only one imagecaptured by the multiple exposure shooting, or with a base image andwithout an image captured by the multiple exposure shooting. In suchcases, the microcomputer 123 does not generate or record an image fileof a multiple combined image. More specifically, if there is only oneimage to be multiple combined, the microcomputer 123 does not generateor record an image file of such a multiple combined image. This canprevent substantially the same image files from being redundantlyrecorded to waste a storage capacity when a multiple combined imagegenerated ends up being substantially the same as its original image. Ifthere is only one image to be multiple combined, the microcomputer 123may perform up to the generation of a multiple combined image but notthe recording of the multiple combined image. This can provide the sameeffect in terms of preventing the recording capacity from being wasted.The foregoing description has dealt with the case where the writtenoriginal image is registered in step S1212 as a first image to bedisplayed on the base image select screen next time. Instead, a baseimage may simply be set to be used next time and the written originalimage may be set as the base image next time.

FIG. 13 is a flowchart illustrating the exit without saving processingin step S823 illustrated in FIG. 8 and step S923 illustrated in FIG. 9described above. The processing illustrated in FIG. 13 is implemented bya program recorded in the nonvolatile memory 130 being loaded into thesystem memory 132 and executed by the microcomputer 123.

In step S1301, the microcomputer 123 refers to written file informationretained in the system memory 132, and searches the recording medium 120for a written image file of an image that is captured for the currentset of multiple exposure shots.

In step S1302, the microcomputer 123 deletes the written image filesearched for and found in step S1301 from the recording medium 120.

In step S1303, the microcomputer 123 refers to the written fileinformation retained in the system memory 132, and determines whetherthere is any written image file that is captured for the current set ofmultiple exposure shots and recorded on the recording medium 120. If itis determined that there is such a file (YES in step S1303), themicrocomputer 123 returns to step S1301 and repeats processing to deletethe remaining image(s). If it is determined that there is no such file,i.e., all images captured for the current set of multiple exposure shotsare determined to have been deleted (NO in step S1303), themicrocomputer 123 proceeds to step S1304.

In step S1304, the microcomputer 123 performs multiple exposure shootinginitialization processing, and ends the exit without saving processing.The multiple exposure shooting initialization processing is the sameprocessing as that in step S1205 illustrated in FIG. 12.

Instead of the multiple exposure shooting setting menu illustrated inFIG. 3 described in the foregoing exemplary embodiment, more detailedpresetting may be performed as to multiple exposure shooting.

FIG. 14 illustrates another display example of the menu screen formaking settings of the digital camera 100 as to the multiple exposureshooting. FIG. 14 illustrates a menu screen 1300 for multiple exposureshooting. The menu screen 1300 is displayed on the display member 118when the user presses the menu button 17 to display a general menu andselects a multiple exposure shooting menu from the general menu.

The menu screen 1300 displays menu items 1301 to 1306. The method ofselecting a menu item and the method of setting a set value from a listof setting candidates for each menu item are similar to thoseillustrated in FIGS. 3A and 3B.

The menu item 1301 is a menu item for selecting how multiple exposureshooting is performed. Any one of setting candidates “off,” “functionand operation priority mode,” and “continuous shooting priority mode”can be selected and set. “Off” is the same as “off” illustrated in FIGS.3A and 3B described above. “Function and operation priority mode” is thesame as “on” illustrated in FIGS. 3A and 3B described above. “Continuousshooting priority mode” is a mode intended for faster continuousshooting speed. The continuous shooting priority mode includes savingthe usage of the buffer memory 122 and omitting the generation andrecording of image files of original images. When the continuousshooting priority mode is selected, the microcomputer 123 does notgenerate display-specific multiple data after each image capturing. Themicrocomputer 123 does not store display-specific multiple data orprevious image capturing time display-specific multiple data into thebuffer memory 122. The microcomputer 123 does not perform the multipleQR and playback processing (FIG. 8) or the multiple first image QR andplayback processing (FIG. 9). Nothing happens when the playback button18 is pressed while the multiple exposure shooting in-process flag is“1”. The microcomputer 123 thus does not perform the exit without savingprocessing (FIG. 13). In such a way, the continuous shooting speed inmultiple exposure shooting can be improved.

The menu item 1302 is a menu item for selecting a method of combinationwhen generating a multiple combined image. Any one of setting candidates“add,” “arithmetic average,” “compare (lighten),” and “compare (darken)”can be selected and set. “Add” is the same as the automatic exposurecontrol function “off” illustrated in FIGS. 3A and 3B described above.“Arithmetic average” is the same as the automatic exposure controlfunction “on” illustrated in FIGS. 3A and 3B described above. “Compare(lighten)” refers to a method in which multiple development data ofcaptured images is compared with an image captured immediately before,and only portions where the image captured immediately before isbrighter are extracted for combination. On the other hand, “compare(darken)” refers to a method in which only portions where the imagecaptured immediately before is darker are extracted for combination.

The menu item 1303 is a menu item for selecting the number of images tobe superimposed for a set of multiple exposure shots. The menu item 1303is the same as the menu item 302 illustrated in FIGS. 3A and 3Bdescribed above.

The menu item 1304 is a menu item for selecting whether to record anoriginal image or images on the recording medium 120. Either one ofsetting candidates “all images” and “multiple image only” can beselected and set. “All images” is selected to record the original image(s) as well. “Multiple image only” is selected not to record theoriginal image(s). When “multiple image only” is set, the microcomputer123 does not record a captured non-multiple image file (original imagefile) in step S605 illustrated in FIG. 6 described above.

The menu item 1305 is a menu item for selecting whether to continueperforming multiple exposure shooting under the same condition as set inFIG. 14 after the number of images captured for multiple exposureshooting reaches the number of images predetermined for multipleexposure shooting and a set of multiple exposure shots is completed.Either one of “once-off” and “repeat” can be set. “Once-off” applies tothe procedure illustrated in FIG. 5 described above. When the number ofimages captured for multiple exposure shooting reaches the number ofimages predetermined for multiple exposure shooting, the microcomputer123 performs the save and exit processing (S506) and changes themultiple exposure shooting necessity setting to “off.” The microcomputer123 ends the multiple exposure shooting mode processing and entersanother shooting mode. In the case of “repeat,” when the number ofimages captured for multiple exposure shooting reaches the number ofimages predetermined for multiple exposure shooting and a set ofmultiple exposure shots is completed (S505) in FIG. 5 described above,the microcomputer 123 does not change the multiple exposure shootingnecessity setting to “off” in the save and exit processing (S506). Afterthe processing in step S505, the microcomputer 123 returns to step S501with the condition set in FIG. 14, and repeats the multiple exposureshooting mode processing from the first image.

The present exemplary embodiment has dealt with the case of usingdevelopment data for multiple combination. However, undeveloped rawimage data may be used for multiple combination.

The control of the microcomputer 123 may be performed by a single pieceof hardware. The entire apparatus may be controlled by distributingprocessing among a plurality of pieces of hardware.

The present invention has been described in detail based on exemplaryembodiments thereof. The present invention is not limited to suchparticular exemplary embodiments, and various aspects are also includedin the present invention without departing from the gist of theinvention. The foregoing exemplary embodiments are just a few exemplaryembodiments of the present invention. The exemplary embodiments may becombined as appropriate.

The foregoing embodiments have dealt with the cases where the presentinvention is applied to a digital camera. This is not restrictive, andexemplary embodiments of the present invention may be applied to anyimaging apparatus that includes an imaging unit. More specifically,exemplary embodiments of the present invention may be applied to adigital camera, a digital video camera, a camera-equipped personalcomputer, a camera-equipped personal digital assistant (PDA), acamera-equipped cellular phone terminal, a camera-equipped music player,a camera-equipped game machine, and a camera-equipped electronic bookreader.

An exemplary embodiment of the present invention may be implemented byexecuting the following processing. The processing includes supplyingsoftware (program) that implements the functions of the foregoingexemplary embodiments to a system or an apparatus via a network or viavarious types of storage media, and a computer (or a central processingunit (CPU) or micro processing unit (MPU)) of the system or apparatusreading and executing the program code. In such a case, the program andthe storage media containing the program constitute exemplaryembodiments of the present invention.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all modifications, equivalent structures, and functions.

This application claims priority from Japanese Patent Application No.2011-101315 filed Apr. 28, 2011, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. An imaging apparatus comprising: a firstreceiving unit configured to receive a capturing instruction to capturean image in a multiple exposure shooting mode; a generation unitconfigured to generate a second composite image by combining a firstimage captured according to the capturing instruction received by thefirst receiving unit with a first composite image generated by combininga plurality of images; a display control unit configured to display, ona display unit, the second composite image generated by the generationunit as a quick review immediately after the first image is captured inresponse to the capturing instruction received by the first receivingunit, and to switch during the quick review, display from the secondcomposite image to the first composite image in response to an operationby a user; and a second receiving unit configured to receive arecapturing instruction to recapture the first image when the firstcomposite image is displayed on the display unit during the quickreview, wherein the display control unit is configured to display thefirst composite image and the second composite image in a playback mode,and wherein the display control unit is configured not to display animage that is captured before shifting to the multiple exposure shootingmode except a base image if shifting to the playback mode is performedwith one or more images captured in the multiple exposure shooting mode,and is configured to display also an image that is captured beforeshifting to the multiple exposure shooting mode if shifting to theplayback mode is performed after the recapturing instruction is receivedby the second receiving unit in a state where only one captured image isretained in the multiple exposure shooting mode.
 2. The imagingapparatus according to claim 1, wherein the display control unit isconfigured to display a monotone image or a warning that an image cannotbe displayed if only one captured image is retained in the multipleexposure shooting mode.
 3. The imaging apparatus according to claim 1,further comprising a retention unit configured to retain data of thefirst image captured according to the capturing instruction, data of thefirst composite image generated by combining the plurality of images,and data of the second composite image generated by combining the firstimage and the first composite image.
 4. A non-transitorycomputer-readable storage medium storing a program that causes acomputer to function as each unit of the imaging apparatus according toclaim
 1. 5. The imaging apparatus according to claim 1, wherein, in acase where a delete instruction of the first image is received by thesecond receiving unit, the generation unit generates a third compositeimage by combining the first composite image and an image captured inresponse to the capturing instruction after reception of the deleteinstruction of the first image.
 6. The imaging apparatus according toclaim 5, wherein, in a case where, after the first image is captured,the capturing instruction is received by the first receiving unitwithout the reception of the delete instruction of the first image, thegeneration unit generates a fourth composite image by combining thesecond composite image and an image captured according to the capturinginstruction.
 7. The imaging apparatus according to claim 3, furthercomprising: wherein, in response to a delete instruction received by thesecond receiving unit, the retention unit removes the data of the firstimage and the data of the second composite image.
 8. The imagingapparatus according to claim 1, wherein the first composite image isable to be displayed in the quick review even if the deletion of thefirst image is not confirmed.
 9. A method for controlling an imagingapparatus, comprising: receiving a capturing instruction to capture animage in a multiple exposure shooting mode; generating a secondcomposite image by combining a first image captured according to thecapturing instruction received with a first composite image generated bycombining a plurality of images; displaying, on a display unit, thesecond composite image generated in a quick review immediately after thefirst image is captured in response to the capturing instructionreceived, and to switch during the quick review, display from the secondcomposite image to the first composite image in response to an operationby a user; and receiving a recapturing instruction to recapture thefirst image when the first composite image is displayed on the displayunit during the quick review, wherein the display unit is configured todisplay the first composite image and the second composite image in aplayback mode, and wherein the display unit is configured not to displayan image that is captured before shifting to the multiple exposureshooting mode except a base image if shifting to the playback mode isperformed with one or more images captured in the multiple exposureshooting mode, and is configured to display also an image that iscaptured before shifting to the multiple exposure shooting mode ifshifting to the playback mode is performed after the recapturinginstruction is received in a state where only one captured image isretained in the multiple exposure shooting mode.